1. Field of the Disclosure
The present disclosure is related to drilling operations and in particular to methods for determining an occurrence of a kick or loss in flowback events.
2. Description of the Related Art
When drilling a wellbore in a formation, drilling fluid is circulated from a surface location to a downhole location by being pumped downward through an inside of a drill string and back to the surface by flowing upward in an annulus between the drill string and the wellbore. When pumping stops, a certain amount of drill fluid, often between 20 to 50 barrels, flows back to the fluid holding tanks. The rate of change in fluid volume (in fluid holding tanks) with time after the pumps have been shut off is known as flowback. Flowback typically comes from various types of surface equipment draining back drilling fluid to the fluid holding tanks. Such flowback, when shutting off the pumps is considered normal. However, a kick can also occur during such occasions, in which fluid flows into the wellbore from the formation. If this formation fluid flow into the wellbore occurs in an uncontrollable manner, a much more dangerous event can occur such as a blowout. Thus, early detection of kicks is of particular interest to drilling operators. The present disclosure therefore provides a method of determining whether a current flowback is a normal flowback or represents a kick.